In orthopedic surgery, bone and joint cutting or drilling is a preliminary step before the insertion of orthopedic hardware (such as pins or screws) into bones or joints during the repair of a bone fracture or installation of a prosthetic device. Accordingly, orthopedic surgeons require bone cutting and drilling skills. These skills are obtained by practicing on bones and joints from cadavers, which are very expensive and in short supply, or on artificial bones manufactured for such practice.
In some instances, surgeons must perform more extensive procedures beyond cutting and/or drilling into the bone to set orthopedic hardware in the bones or joints. For example, after drilling a hole in the bone or joint, the surgeon might administer a bone structure reinforcement compound, such as a bone cement compound, through a percutaneous or injection method into the bone or joint. The bone cement penetrates the cancellous bone area. A pin or screw may then be inserted into the hole, and the bone cement hardens therearound to set the pin or screw within the reinforced bone. The penetration of the bone cement through an artificial cancellous bone area is limited in current artificial bones because currently designed artificial bones typically include a closed cell artificial cancellous bone area having no interstices or passages between cells for the bone cement to travel through. Moreover, these currently designed artificial bones do not have characteristics and properties that correspond to other characteristics and properties of mammalian bones.
Therefore, there exists a need for improved artificial bones and joints that perform like mammalian bone when subjected to the procedures designed for fracturing and repairing such bones, for augmenting the bone structure with reinforcing compounds, such as bone cements, and for other static and dynamic biomechanical experimentation.
Moreover, current artificial bones are typically manufactured by reaction injection molding a lower density polyurethane closed cell artificial cancellous bone on a pin or mandrel in a first mold, then molding a higher density polyurethane artificial cortical bone around the artificial cancellous bone in a second larger mold, then removing the pin or mandrel. Because an open cell artificial cancellous bone cannot be reaction injection molded using the same method used for a closed cell artificial cancellous bone, there also exists a need for improved methods of making improved artificial bones and joints using open cell artificial cancellous bone.